Last year I had a brand new Worcester Bosch boiler fitted, a Greenstar 25i ErP NG Combi to be exact. Recently, well, the last month or so, there have been some very loud noises coming from the pipework leading out from the boiler, like banging popping noises, as though there is some build up of pressure or something. It actually woke me up this morning at 3am the bang was so loud. It usually does it in the early hours of the morning when the heating has been switched off for a few hours, but I have more recently noticed the noise when the heating has been switched on aswell. The boiler is due its first service in March, I am going to call the company who fit it this week, but I would like to be armed with some sort of knowledge as to what may be causing this. Thank you in advance
This is only a suggestion, Ben, but it could be excessive mains water pressure. A combi boiler takes its supply for hot water directly from the mains.
If this is the case, a simple water pressure regulator fitted to the rising main would fix it. It's a known fact that mains water pressure rises considerably during the night (not so many using it.)
I bled the system as suggested, (I'm not that bad waterboatman, I do know how to do that), made no difference. Turned out it was a build up of limescale! Strange as this never happened in my old boiler but it seems to be ok now.